Screen Sizes Impact on Picture and Sound - Dolby Laboratories Inc.

This example showed a correlation far more precise than the author anticipated,
and it is doubtful that such a precise proportionality would be found in every
case! Nevertheless, the relationship clearly shows that as the screen gets bigger,
the limiting contrast goes down.
Not shown in the table is a further test with only a small illuminated area,
approximately two square feet—here the limiting contrast was in excess of
800:1, presumably greater than the film’s own contrast capability.
A simple procedure is described in the addendum at the end of this article,
which gives an approximate method of calculating anticipated limiting contrast,
taking into account room and screen dimensions and material reflectivity.
Acoustic Issues
It may seem surprising that screen size also has a significant effect on
auditorium acoustics.
One of the major challenges for the design of any performance room is to avoid
pronounced room resonances. These are particular frequencies which “ring.”
The effect can best be imagined by a scale played on the low-frequency notes of
a church organ—in a badly designed space, certain notes will sound much
louder than others.
The best way to avoid these effects is to avoid repetition of a single dimension,
or a multiple of a single dimension. For example, a sphere is a very bad shape,
having a single dimension repeating. A cube is a bad shape, with the same
length, breadth, and height dimension. A square room with a height half of the
length would also be bad, as again, a certain note would be emphasized.
Now, acousticians analyzing the best-sounding concert halls find that there are
some standard ratios that minimize the number of standing waves or resonances.
The best ratio of length to breadth is about 1.55 to 1, and a height-to-width ratio
of about 0.67, as shown in Figure 7. It is interesting that both these numbers
(1.55 and 1/0.67) are close to (1.55)/2, 1.62, which is known as the Golden
Ratio 3
. The Golden Ratio has been a fundamental principle of architecture and
design for thousands of years.
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